20121107152600.0 0741-9023 0741-9023 District of Columbia Preservation tech notes 0741-9023 0741-9023 Preservation tech notes 0741-9023 hathi HathiTrust https://catalog.hathitrust.org/Record/002476347 1990/1990 2024-03-01 no.1-2 1990; no.19; no.17; no.15; no.6; no.32; no.29; no.27; no.26; no.46; no.45; no.42; no.41; no.40; no.39; no.38 no.1-2 1990; no.19; no.17; no.15; no.6; no.32; no.29; no.27; no.26; no.46; no.45; no.42; no.41; no.40; no.39; no.38 Preserved [National Park Service, Preservation Assistance Division, 1984- Preservation tech notes / National Park Service, U.S. Department of the Interior. 0741-9023 Preservation tech notes